Currently, the market for cellular mobile equipment consists of suppliers of mobile networks and mobile phones, operators, and customers. Due to the general lack of capacity in the present mobile networks, as well as due to the introduction of new (potential) applications and services in need of high bandwidth, there is an urge on further increasing capacity in mobile network systems. New applications and services, often including the transmission of e.g. pictures and/or movies, provides that the demand for bandwidth is much larger than current mobile networks are able to supply.
To ensure that a need for necessary bandwidth in coming high-bandwidth applications and services, large investments in developments of a new infrastructure are made by the suppliers of mobile networks. The operators, on their side, are forced to purchase the necessary new licenses needed in order to operate the new infrastructure. At the end, it is the customer who pays the price for combined efforts accomplished by suppliers of mobile networks and operators, making end-customers costs for high-bandwidth mobile telephone services become unrealistically high. Also second-generation mobile networks, such as GSM, suffer from a general lack of capacity and are in demand of an increased growth of capacity.
The US patent document US 2002/0014990 by Kimura discloses a “Radio Communication Device and Method of Measuring Distance”. A distance measurement is accomplished by sending a pilot signal between two portable telephones via a radio interface for short distance.
Patent application GB-A-2 356 532 teaches how to improve the quality of radio signals by switching calls between the cellular network and direct communication between mobile stations by utilizing the frequency bands of the cellular network when the signal quality is better for direct communication then for communication in the network. This is provided through combination techniques for diversity, i.e., the utilization of several antennas receiving the same signal, whereby the signal received at the antenna with the largest signal strength is utilized. GB-A-2 356 532 utilizes the same frequency band for cellular network carried traffic and direct communication between mobile stations. At direct communication the invention in GB-A-2 356 532 so to speak “steals” capacity from the traffic channel TCH in a GSM system, which not aims to extend the system call capacity. Moreover GB-A-2 356 532 does not suggest a cellular phone.